/*
* DropShards drops all given shards in a relation. The id, name and schema
* for the relation are explicitly provided, since this function may be
* called when the table is already dropped.
*
* We mark shard placements that we couldn't drop as to be deleted later, but
* we do delete the shard metadadata.
*/
static int
DropShards(Oid relationId, char *schemaName, char *relationName,
List *deletableShardIntervalList)
{
ListCell *shardIntervalCell = NULL;
int droppedShardCount = 0;
BeginOrContinueCoordinatedTransaction();
/* At this point we intentionally decided to not use 2PC for reference tables */
if (MultiShardCommitProtocol == COMMIT_PROTOCOL_2PC)
{
CoordinatedTransactionUse2PC();
}
foreach(shardIntervalCell, deletableShardIntervalList)
{
List *shardPlacementList = NIL;
ListCell *shardPlacementCell = NULL;
ShardInterval *shardInterval = (ShardInterval *) lfirst(shardIntervalCell);
uint64 shardId = shardInterval->shardId;
char *quotedShardName = NULL;
char *shardRelationName = pstrdup(relationName);
Assert(shardInterval->relationId == relationId);
/* Build shard relation name. */
AppendShardIdToName(&shardRelationName, shardId);
quotedShardName = quote_qualified_identifier(schemaName, shardRelationName);
shardPlacementList = ShardPlacementList(shardId);
foreach(shardPlacementCell, shardPlacementList)
{
ShardPlacement *shardPlacement =
(ShardPlacement *) lfirst(shardPlacementCell);
char *workerName = shardPlacement->nodeName;
uint32 workerPort = shardPlacement->nodePort;
StringInfo workerDropQuery = makeStringInfo();
MultiConnection *connection = NULL;
uint32 connectionFlags = FOR_DDL;
char storageType = shardInterval->storageType;
if (storageType == SHARD_STORAGE_TABLE)
{
appendStringInfo(workerDropQuery, DROP_REGULAR_TABLE_COMMAND,
quotedShardName);
}
else if (storageType == SHARD_STORAGE_COLUMNAR ||
storageType == SHARD_STORAGE_FOREIGN)
{
appendStringInfo(workerDropQuery, DROP_FOREIGN_TABLE_COMMAND,
quotedShardName);
}
connection = GetPlacementConnection(connectionFlags, shardPlacement, NULL);
RemoteTransactionBeginIfNecessary(connection);
if (PQstatus(connection->pgConn) != CONNECTION_OK)
{
uint64 placementId = shardPlacement->placementId;
ereport(WARNING, (errmsg("could not connect to shard \"%s\" on node "
"\"%s:%u\"", shardRelationName, workerName,
workerPort),
errdetail("Marking this shard placement for "
"deletion")));
UpdateShardPlacementState(placementId, FILE_TO_DELETE);
continue;
}
MarkRemoteTransactionCritical(connection);
ExecuteCriticalRemoteCommand(connection, workerDropQuery->data);
DeleteShardPlacementRow(shardPlacement->placementId);
}
/*
* OpenTransactionsToAllShardPlacements opens connections to all placements
* using the provided shard identifier list and returns it as a shard ID ->
* ShardConnections hash. connectionFlags can be used to specify whether
* the command is FOR_DML or FOR_DDL.
*/
HTAB *
OpenTransactionsToAllShardPlacements(List *shardIntervalList, int connectionFlags)
{
HTAB *shardConnectionHash = NULL;
ListCell *shardIntervalCell = NULL;
List *newConnectionList = NIL;
shardConnectionHash = CreateShardConnectionHash(CurrentMemoryContext);
/* open connections to shards which don't have connections yet */
foreach(shardIntervalCell, shardIntervalList)
{
ShardInterval *shardInterval = (ShardInterval *) lfirst(shardIntervalCell);
uint64 shardId = shardInterval->shardId;
ShardConnections *shardConnections = NULL;
bool shardConnectionsFound = false;
List *shardPlacementList = NIL;
ListCell *placementCell = NULL;
shardConnections = GetShardHashConnections(shardConnectionHash, shardId,
&shardConnectionsFound);
if (shardConnectionsFound)
{
continue;
}
shardPlacementList = FinalizedShardPlacementList(shardId);
if (shardPlacementList == NIL)
{
/* going to have to have some placements to do any work */
ereport(ERROR, (errmsg("could not find any shard placements for the shard "
UINT64_FORMAT, shardId)));
}
foreach(placementCell, shardPlacementList)
{
ShardPlacement *shardPlacement = (ShardPlacement *) lfirst(placementCell);
MultiConnection *connection = NULL;
WorkerNode *workerNode = FindWorkerNode(shardPlacement->nodeName,
shardPlacement->nodePort);
if (workerNode == NULL)
{
ereport(ERROR, (errmsg("could not find worker node %s:%d",
shardPlacement->nodeName,
shardPlacement->nodePort)));
}
connection = StartPlacementConnection(connectionFlags,
shardPlacement,
NULL);
ClaimConnectionExclusively(connection);
shardConnections->connectionList = lappend(shardConnections->connectionList,
connection);
newConnectionList = lappend(newConnectionList, connection);
/*
* Every individual failure should cause entire distributed
* transaction to fail.
*/
MarkRemoteTransactionCritical(connection);
}
/*
* OpenTransactionsForAllTasks opens a connection for each task,
* taking into account which shards are read and modified by the task
* to select the appopriate connection, or error out if no appropriate
* connection can be found. The set of connections is returned as an
* anchor shard ID -> ShardConnections hash.
*/
HTAB *
OpenTransactionsForAllTasks(List *taskList, int connectionFlags)
{
HTAB *shardConnectionHash = NULL;
ListCell *taskCell = NULL;
List *newConnectionList = NIL;
shardConnectionHash = CreateShardConnectionHash(CurrentMemoryContext);
connectionFlags |= CONNECTION_PER_PLACEMENT;
/* open connections to shards which don't have connections yet */
foreach(taskCell, taskList)
{
Task *task = (Task *) lfirst(taskCell);
ShardPlacementAccessType accessType = PLACEMENT_ACCESS_SELECT;
uint64 shardId = task->anchorShardId;
ShardConnections *shardConnections = NULL;
bool shardConnectionsFound = false;
List *shardPlacementList = NIL;
ListCell *placementCell = NULL;
shardConnections = GetShardHashConnections(shardConnectionHash, shardId,
&shardConnectionsFound);
if (shardConnectionsFound)
{
continue;
}
shardPlacementList = FinalizedShardPlacementList(shardId);
if (shardPlacementList == NIL)
{
/* going to have to have some placements to do any work */
ereport(ERROR, (errmsg("could not find any shard placements for the shard "
UINT64_FORMAT, shardId)));
}
if (task->taskType == MODIFY_TASK)
{
accessType = PLACEMENT_ACCESS_DML;
}
else
{
/* can only open connections for DDL and DML commands */
Assert(task->taskType == DDL_TASK || VACUUM_ANALYZE_TASK);
accessType = PLACEMENT_ACCESS_DDL;
}
foreach(placementCell, shardPlacementList)
{
ShardPlacement *shardPlacement = (ShardPlacement *) lfirst(placementCell);
ShardPlacementAccess placementModification;
List *placementAccessList = NIL;
MultiConnection *connection = NULL;
WorkerNode *workerNode = FindWorkerNode(shardPlacement->nodeName,
shardPlacement->nodePort);
if (workerNode == NULL)
{
ereport(ERROR, (errmsg("could not find worker node %s:%d",
shardPlacement->nodeName,
shardPlacement->nodePort)));
}
/* add placement access for modification */
placementModification.placement = shardPlacement;
placementModification.accessType = accessType;
placementAccessList = lappend(placementAccessList, &placementModification);
if (accessType == PLACEMENT_ACCESS_DDL)
{
List *placementDDLList = BuildPlacementDDLList(shardPlacement->groupId,
task->relationShardList);
/*
* All relations appearing inter-shard DDL commands should be marked
* with DDL access.
*/
placementAccessList = list_concat(placementAccessList, placementDDLList);
}
else
{
List *placementSelectList =
BuildPlacementSelectList(shardPlacement->groupId,
task->relationShardList);
/* add additional placement accesses for subselects (e.g. INSERT .. SELECT) */
placementAccessList =
list_concat(placementAccessList, placementSelectList);
}
/*
* Find a connection that sees preceding writes and cannot self-deadlock,
* or error out if no such connection exists.
*/
connection = StartPlacementListConnection(connectionFlags,
placementAccessList, NULL);
ClaimConnectionExclusively(connection);
shardConnections->connectionList = lappend(shardConnections->connectionList,
connection);
newConnectionList = lappend(newConnectionList, connection);
/*
* Every individual failure should cause entire distributed
* transaction to fail.
*/
MarkRemoteTransactionCritical(connection);
}
